The flow of vehicle traffic has been studied extensively in the last few decades. Traffic control software including traffic based algorithms have been implemented to control the timing of traffic signal lights that regulate vehicle traffic.
A typical signalized intersection includes a traffic controller that is hard wired to the signal lights at the intersection for control thereof. The traffic controller includes algorithms for operating the signal lights. To more efficiently maintain the flow of traffic along a busy roadway with several signalized intersections, operation of the signal lights is coordinated among the traffic controllers associated therewith.
Efforts have been made to simplify the infrastructure used for monitoring and controlling signalized intersections. For example, U.S. Published Patent Application No. 2008/0074289 discloses a wireless traffic signal light management system. The system includes a master controller, wireless nodes dispersed in a geographic area and traffic signal lights also dispersed in the geographic area. The traffic signal lights are communicatively coupled to the master controller via the wireless nodes. Each wireless node is associated with a distinct Internet protocol address, and a wireless communication link provides Internet protocol based communications between the wireless nodes and the master controller. The wireless nodes receive control data packets for the communicatively coupled traffic signal lights from the master controller via the wireless communication link. The control data packets include the distinct Internet protocol address and operational instructions for at least one traffic signal light communicatively coupled to the wireless node, and each traffic signal light is responsive to the operational instructions in the control data packets.
Efforts have also been made to measure traffic flow by sampling a portion of actual travel times for vehicles in the traffic stream. Several cities in the United States, such as Houston and Boston, have been making measurements based on signals available from a point-to-point networking protocol commonly referred to as Bluetooth.
The majority of consumer electronic devices come equipped with Bluetooth wireless capability to communicate with other devices in close proximity. Bluetooth enabled devices can communicate with other Bluetooth enabled devices anywhere from 1 meter to about 100 meters, depending on the power rating of the Bluetooth devices. The Bluetooth protocol uses an electronic address, or tag, called a Media Access Control address, or MAC address.
A vehicle containing a detectable Bluetooth device is observed at successive detection stations. The MAC address and time of detection is logged, and the information is used to obtain an accurate sample of the travel time and an average speed. This type of information is generally used for measuring traffic flow.
There are other types of systems that provide traffic information to travelers via messages displayed on fixed road signs. The road signs are remotely programmable to provide messages about travel times and conditions on the roadway. A drawback of this approach is that the fixed road signs are expensive. Another drawback is that the travelers may already be on the road if the message being displayed is directed to an impending delay due to an accident.
Even in view of the advances made in traffic monitoring and traffic management, there is still a need to improve upon these activities.